How Nichia Created the First Practical Blue LED Electrodes
A foundational patent describing the specific metal contacts needed to make gallium nitride LEDs efficient and commercially viable.
Original patent title: “Gallium nitride-based III-V group compound semiconductor device and method of producing the same”
A foundational patent describing the specific metal contacts needed to make gallium nitride LEDs efficient and commercially viable. Granted to Nichia Chemical Industries Ltd in 1996 with 58 claims and 251 forward citations, and it is now in the public domain.
Key facts
Coverage
What does this patent actually cover?
This patent details the construction of a light-emitting diode (LED) using gallium nitride, specifically focusing on how to create reliable electrical connections. It describes a 'second electrode' made of nickel or a nickel-gold alloy that sits on top of the p-type semiconductor layer. To ensure this connection works properly, the patent specifies that the electrode must be annealed—heated to at least 400 degrees Celsius—to form an ohmic contact, which allows electricity to flow easily into the semiconductor. This was critical because, without this specific metal-to-semiconductor interface, the device would not efficiently inject the current required to produce light.
The gap
What does this patent NOT cover?
- Does not cover the underlying growth process of the gallium nitride crystal itself.
- Does not cover LEDs made from materials other than gallium nitride-based III-V compounds.
- Does not cover electrode materials that do not utilize nickel or nickel-gold combinations as specified.
- Does not cover non-ohmic contact methods that rely on different electrical physics.
These exclusions are unique to PatentBrief — derived from the actual claim language, not patent-office boilerplate.
What made this novel
The innovation was realizing that a thin, light-transmitting nickel-based layer, when properly annealed, could provide the necessary electrical conductivity without blocking the light generated by the semiconductor underneath.
The Patent Drawing
Schematic visualization of the patent's claim structure. Hand-drawn diagrams in progress for each landmark patent.
Where you've seen this
Real-world examples
Early high-brightness blue LED indicators
White LED backlighting for LCD screens
General-purpose LED light bulbs
Why it matters
The bigger picture
This patent was a key piece of the puzzle in the invention of the blue LED, an achievement that earned Shuji Nakamura and his colleagues global recognition. By solving the problem of creating stable electrical contacts for gallium nitride, Nichia enabled the mass production of blue, green, and eventually white LEDs. This technology fundamentally changed the lighting industry, transitioning the world from inefficient incandescent and fluorescent bulbs to energy-efficient solid-state lighting.
Filed
April 28, 1994
Granted
October 8, 1996
Market context
Who's building on this
Companies in this space
Nichia Corporation remains a dominant force in LED manufacturing, continuing to refine the gallium nitride processes established in this era. Major global semiconductor and lighting firms like Cree (now Wolfspeed), Lumileds, and Samsung have all built their LED product lines upon the foundational work of gallium nitride semiconductor devices.
Market impact
This patent helped trigger the transition to solid-state lighting, effectively killing off the market for traditional incandescent bulbs. It enabled the creation of the multi-billion dollar white LED industry, which is now the standard for everything from smartphone screens to street lighting.
Claim 1 — Plain English
What this patent covers
This patent details the construction of a light-emitting diode (LED) using gallium nitride, specifically focusing on how to create reliable electrical connections. It describes a 'second electrode' made of nickel or a nickel-gold alloy that sits on top of the p-type semiconductor layer. To ensure this connection works properly, the patent specifies that the electrode must be annealed—heated to at least 400 degrees Celsius—to form an ohmic contact, which allows electricity to flow easily into the semiconductor. This was critical because, without this specific metal-to-semiconductor interface, the device would not efficiently inject the current required to produce light.
The clever bit
The innovation was realizing that a thin, light-transmitting nickel-based layer, when properly annealed, could provide the necessary electrical conductivity without blocking the light generated by the semiconductor underneath.
What it does not cover
- Does not cover the underlying growth process of the gallium nitride crystal itself.
- Does not cover LEDs made from materials other than gallium nitride-based III-V compounds.
- Does not cover electrode materials that do not utilize nickel or nickel-gold combinations as specified.
- Does not cover non-ohmic contact methods that rely on different electrical physics.
Patent Journey
From filing to expiry
PatentBrief Score
Impact Score
Strong
Citation count
40/40
Highly cited
Claim breadth
20/20
Very broad protection
Recency
0/20
Older than 20 years
Assignee scale
0/20
Independent or smaller assigneeassigneeThe entity that owns the patent — usually the inventor's employer or a company.Read more →
PatentBrief Impact Score — based on citation count, claim breadth, recency, and assignee scale. Not a legal assessment.
Heuristic Value Estimate
What this patent might be worth
$101K – $323K
Midpoint $202K · expired or expiring · industry ×1.4
Heuristic only — blends forward/backward citation counts, claim scope, time remaining, litigation history, and CPC-derived industry baseline. Real valuations need a professional appraisal.
The original legal language
Original claims
58 claims as filed with the patent office.
Concepts involved
Citations
Patent lineage
Cite this patent
Nakamura, S., Yamada, T., Senoh, M., Yamada, M., & Bando, K. (1996). How Nichia Created the First Practical Blue LED Electrodes (U.S. Patent No. 5,563,422). U.S. Patent and Trademark Office. https://patentbrief.org/patent/us/5563422/blue-led-gallium-nitride
Auto-generated from the patent record. Double-check author order and the issue date against the official USPTO document before submitting.
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Common Questions
Frequently Asked Questions
What does How Nichia Created the First Practical Blue LED Electrodes cover?
A foundational patent describing the specific metal contacts needed to make gallium nitride LEDs efficient and commercially viable.
Who owns patent US 5563422?
Nichia Chemical Industries Ltd owns this patent, granted in 1996.
When does this patent expire?
This patent has expired and is now in the public domain — anyone can use the invention freely.
What is patent US 5563422 cited by?
This patent has been cited by 251 later patents that build on its ideas.
What problem does this patent solve?
This patent was a key piece of the puzzle in the invention of the blue LED, an achievement that earned Shuji Nakamura and his colleagues global recognition. By solving the problem of creating stable electrical contacts for gallium nitride, Nichia enabled the mass production of blue, green, and eventually white LEDs. This technology fundamentally changed the lighting industry, transitioning the world from inefficient incandescent and fluorescent bulbs to energy-efficient solid-state lighting.
What does this patent NOT cover?
Does not cover the underlying growth process of the gallium nitride crystal itself.
Patent monitoring